[OE-core] opkg pkg_prerm on package update

[Andreas Müller]

Hi,

although opkg 0.2 -> 0.3 is long ago I noticed a change in behaviour
when updating a package:

* 0.2.x did not call pkg_prerm
* 0.3.x calls pkg_prerm

Is calling pkg_prerm a valid behaviour when updating a package?

Why I ask this:

systemd.bbclass does

* stop a service on pkg_prerm
* restart a service on pkg_postinst

This default causes trouble when updating displaymanager within a
X-session: Displaymanager is stopped - killing the update process...

For opkg 0.2.x a workaround was to override pkg_postinst avoiding
systemd service restart. This worked properly for all my use cases:
update / remove.

With the 0.3.x behaviour I can help myself by overriding pkg_prerm and
pkg_postinst but when removing displaymanger it is not stopped.

Thoughts?

Andreas